Lorentzen M ; Maage A ; Julshamn K ;

Aquaculture Nutrition vol. 2 (2)   pp. 121-125, 1996

Inst. Nutrition, Directorate Fish., PO Box 185, N-5002 Bergen, Norway

This experiment was conducted to study whether practical fish meal based feeds for Atlantic salmon, Salmo salar L., require manganese (Mn) supplementation. Three thousand parr of initial weight 4.7 g were randomly distributed into 10 tanks and given a fish meal based diet, either unsupplemented or supplemented with 5, 10, 50 or 100 mg Mn/kg (as MnSO sub(4)*H sub(2)O) for 12 weeks. The basal diet contained 4.8 mg Mn/kg. Mn concentration in vertebrae and whole fish responded linearly to supplemented Mn up to a level of 10 mg/kg and then reached a plateau. Dietary Mn supplementation did not affect weight gain, liver Mn concentration, blood haemoglobin concentration or haematocrit. To the practical feed, a supplementary level of 10 mg Mn/kg, giving a total Mn concentration of 15 mg/kg diet, was necessary to maintain normal Mn status as determined by Mn level in vertebrae and whole fish. However, taking into account the variable Mn content in fish meal and the uncertainty about availability, we recommend a general supplementation of 15 mg Mn/kg

Fish culture ;  Manganese ;  Diets ;  Nutritional requirements ;  Food additives ;  Fish meal ;  Salmo salar ;